Plasticized polyvinyl chloride

ABSTRACT

Esters of cyclohexane polycarboxylic acids are used as plasticisers for polyvinyl chloride to enable products with comparable mechanical properties to be obtained using less polyvinyl chloride. Use of these esters also produces formulations with increased stability to ultra-violet light, improved low temperature properties, lower viscosity and improved processability as well as reduced smoke on burning. The esters of cyclohexane polycarboxylic acids may be used alone or in admixture with other plasticisers when the esters of cyclohexane polycarboxylic acids may act as viscosity depressants. Fast fusing plasticisers may also be included. The formulations are particularly useful in the production of a range of goods from semi-rigid to highly flexible materials and are particularly useful in the production of medical materials such as blood bags and tubing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national stage of International PatentApplication No. PCT/EP02/10945, filed 25 Sep. 2002, which claimspriority to GB 0123018.4 filed 25 Sep. 2001; GB 0123019.2 filed 25 Sep.2001; GB 0123020.0 filed 25 Sep. 2001; GB 0123021.8 filed 25 Sep. 2001;GB 0123022.6 filed 25 Sep. 2001; GB 0123134.9 filed 26 Sep. 2001; GB0123221.4 filed 27 Sep. 2001; and GB 0201188.0 filed 21 Jan. 2002.

FIELD OF INVENTION

The present invention relates to improved polyvinyl chloridecompositions. Polyvinyl chloride is widely used in a variety ofapplications. Polyvinyl chloride is commonly used in a mixture with aplasticiser. The nature of the polyvinyl chloride, the nature of theplasticiser and the proportions of the two materials are chosen toprovide a polyvinyl chloride composition having the desired propertiesfor a particular application. Examples of the major uses of plasticisedpolyvinyl chloride compositions include wire and cable coating, otherelectrical applications such as plugs, film, foil and sheeting,flooring, wall covering, roofing and membranes. Other uses include filmssuch as stationary films, adhesives tapes and agricultural films.Polyvinyl chloride is also used in medical applications such as bloodbags, tubing and bottle caps, further uses include footwear, pipe andgultering and fabric coating.

BACKGROUND OF THE INVENTION

Phthalate esters are widely used as plasticisers for polyvinyl chloride.Examples of phthalate esters that are used include dioctyl phthalate,di-isononyl phthalate, di-isodecyl phthalate, di-isooctly phthalate,diisoheptyl phthalate and di-2ethyl hexyl phthalate (DEHP). Typicalcommercial materials include the Jayflex plasticisers, Jayflex® DINP andJayflex® DIDP available from ExxonMobil Chemical and the Palatinol®plasticisers marketed by BASF and Vestinol® from Oxeno.

The alcohols from which the plasticiser esters are made are generallyobtained by either olefin oligomerisation followed by hydroformylationor by hydroformylation of olefins to form aldehydes followed by aldehydedimerization, generally by an aldol reaction. The alkyl groups of theesters therefore vary in size and structure according to the process andraw materials used to produce the alcohols. Typical plasticiser esterscontain alkyl groups of 5 to 13 carbon atoms, particularly 7 to 13carbon atoms, and have varying degrees of branching. The size andstructure of the alkyl group helps determine the volatility andgellation temperature of the plasticiser and is therefore chosenaccording to the application in which the plasticised polyvinyl chlorideis to be used. For instance flooring, where stain resistance isrequired, high volatility, at least of the surface layer, is desired.

There is a constant need to improve the properties of plasticisers toprovide polyvinyl chloride compositions having improved properties.There is also a need for alternative plasticisers. In addition there isa need to improve the properties of plasticisers. It has also beenproposed that esters of cyclohexane carboxylic acids particularly estersof cyclohexane dicarboxylic acids may be used as plasticisers forpolyvinyl chloride. For example United States defensive patentpublication T 864003 discloses the use of cyclohexane 1–4 dicarboxylateesters as plasticisers. In particular T 864003 discloses bis(2-ethylhexyl) cyclohexane 1–4 dicarboxylate as a plasticiser andcompares its performance with bis (2-ethylhexyl) phthalate and findsimproved low temperature performance and comparable mechanicalproperties when using the cyclohexane based material. Such materials arealso described in a Union Carbide Chemicals Company TechnicalInformation bulletin Number F-7893B of November 1957 entitled “Flexol”Plasticiser CC-55.

More recently Gebrauchsmuster DE 29824628 and PCT Publication WO99/32427 disclose a range of plasticisers based on cyclohexanedicarboxylic acid prepared by the hydrogenation of the correspondingphthalates. According to DE 29824628 and WO 99/32427 the cyclohexanoateshave lower density and viscosity and yield an improvement in the lowtemperature flexibility of the plastics when compared with thecorresponding phthalates. Properties such as the Shore hardness andother mechanical properties of the resultant plastics are said to beidentical to those obtained with the use of phthalates. According to WO99/32427 the cyclohexanoates exhibit better workability in a dry blendand also have advantages through the markedly lower viscosity whencompared with the corresponding phthalates.

Japanese Patent Application Publication Number P 2001 207002 describescyclohexane dicarboxylic acid esters derived from mixtures containingfrom 80 to 97 wt % of C₉ branched alcohols. Japanese Patent PublicationNumber P 2001-207002 compares, as plasticisers, these esters withdioctyl phthalate and finds improved cold resistance, viscosity andviscosity stability over time.

We have now found that cyclohexanoates may be used as plasticisers inpolyvinyl chloride compositions to reduce the amount of polyvinylchloride required to produce compositions having comparable mechanicalproperties to those obtained when using phthalates as the plasticiser.

Accordingly, the present invention provides the use of an ester ofcyclohexane polycarboxylic acids as plasticisers for polyvinyl chloridecompositions to enable the production of a composition having comparablemechanical properties with a reduced amount of polyvinyl chloride. Insome embodiments the amount of polyvinyl chloride can be reduced by 0.05wt %, 1.5 wt %, 2.0 wt %, 2.5 wt % and 3 wt % or any range thereofresulting in 4 to 7% cost savings at comparably plasticiser price.

DESCRIPTION OF THE DRAWINGS

FIG. 1 plots the viscosity and density of esters versus the carbonnumber of the alcohol used to make the ester.

FIG. 2 plots the relative shore D hardness versus plasticiser content.

FIG. 3 plots the Brookfield viscosity of the plastisols versus time.

FIG. 4 plots melt viscosity versus shear rate.

FIG. 5 plots mechanical properties of some foil and sheetingformulations.

FIG. 6 plots weight change versus time.

FIG. 7 plots viscosity change versus time.

In particular, the present invention provides polyvinyl chloridecomposition based on esters of cyclohexane polycarboxylic acids asplasticisers having Shore hardness and tensile strength comparable tocompositions based on phthalate plasticisers but requiring lesspolyvinyl chloride than when the phthalate plasticiser is used. Thisresults in considerable economic benefits, especially in productsprepared from plastisols.

The invention is applicable across the range of plasticised polyvinylchloride materials. It is applicable to the production of semi-rigidpolyvinyl chloride compositions which typically contain from 10 to 40parts, preferably 15 to 35 parts, more preferably 20 to 30 parts ofplasticiser per 100 parts of polyvinyl chloride. The invention is alsoapplicable to flexible polyvinyl chloride compositions which typicallycontain from 40 to 60 parts preferably 44 to 56 parts, more preferablyfrom 48 to 52 parts per 100 parts of polyvinyl chloride and also to thehighly flexible compositions which typically contain from 70 to 110parts, preferably 80 to 100 parts, more preferably 90 to 100 parts ofplasticiser per 100 parts of polyvinyl chloride. The parts being byweight.

The semi-rigid compositions are typically used for the production ofpipes, some wire and cable coatings, floor tiles, window shades, films,blood bags and medical tubing. Flexible compositions are typically usedfor the production of sheeting, upholstery, medical tubing, gardenhoses, pool liners, water beds and the like. Very flexible compositionsare used in the production of coated cloth, toys, shoe soles and thelike. The esters of cyclohexane polycarboxylic acid are particularlyuseful in the production of medical articles such as blood bags andmedical tubing and in toys and materials used for food contact such asbottle caps and films where di-2-ethyhexyl phthalate has traditionallybeen used and there are some concerns about its toxicity.

In another aspect of the present invention the esters of the cyclohexanepolycarboxylic acid are used together with other plasticisers. Forexample, the ester of the cyclohexane polycarboxylic acid may be usedwith plasticisers such as adipate esters, phthalate esters, trimellitateesters and various polymeric plasticisers, some of which have beendescribed previously. When used in plasticiser blends the relativeproportions of the plasticisers that are used will depend upon thedesired properties. However we prefer to use at least 5 wt %, morepreferably at least 10 wt %, more preferably at least 15 wt %, morepreferably at least 20 wt %, more preferably at least 25 wt %, morepreferably at least 30 wt %, more preferably at least 35 wt %, morepreferably at least 40 wt %, more preferably at least 45 wt %, morepreferably at least 50 wt %, more preferably at least 55 wt %, morepreferably at least 60 wt %, more preferably at least 65 wt %, morepreferably at least 70 wt %, more preferably at least 75 wt %, morepreferably at least 80 wt %, more preferably at least 85 wt %, morepreferably at least 90 wt %, of the ester of the cyclohexanepolycarboxylic acid based on the total weight of plasticiser present. Ina preferred embodiment wherein a mixture of plasticisers is used and oneof the plasticisers is a phthalate, the mixture preferably comprises nomore than 95 wt % cyclohexane polycarboxylic acid. Preferred rangesinclude between 0.01 and 95 wt %, more preferably 5 to 90 wt %, morepreferably 10 to 80 wt %, more preferably 20 to 70 wt %, more preferably30 to 60 wt % of the ester of the cyclohexane polycarboxylic acid.

We have also found that cyclohexane polycarboxylic acid esters impart animproved stability to ultra-violet light when used as plasticisers inpolyvinyl chloride compositions. This improved stability leads to longerservice life for materials made from the polyvinyl chloride especiallyin an environment where they are subjected to sunlight. Throughout thisapplication ultra-violet light stability is measured in the QUV testwhich is ASTM G 53–84. This is particularly useful where the plasticisedpolyvinyl chloride composition is to be used in outdoor applications. Inparticular, this is useful in applications such as roofing, tarpaulinsand tents, films such as adhesive tapes and agricultural films, shoesand automobile interiors.

In a further embodiment the present invention therefore provides aplasticised polyvinyl chloride composition containing from 20 to 100parts by weight, preferably 30 to 90 parts by weight, more preferably 40to 80 parts by weight, more preferably 50 to 70 parts by weight of aplasticiser composition containing one or more cyclohexanepolycarboxylic acid esters as plasticiser per 100 parts of polyvinylchloride said composition having a stability to ultra-violet lightindicated by the low development of colour in the QUV test over 456hours in a formulation containing 100 parts of solvic 367 polyvinylchloride, 50 parts of plasticiser, 5 parts of Durcal calcium carbonatefiller and 2 parts of LZB 320 stabiliser.

In a further embodiment the present invention provides the use of aplasticised polyvinyl chloride composition containing from 20 to 100parts by weight preferably 30 to 90 parts by weight, more preferably 40to 80 parts by weight, more preferably 50 to 70 parts by weight of aplasticiser composition containing one or more cyclohexanepolycarboxylic acid esters as plasticiser per 100 parts by weight ofpolyvinyl chloride in the production of articles said composition havinga stability to ultra-violet light, as indicated by the low developmentof colour in the QUV test over 456 hours in a formulation containing 100parts of solvic 367 polyvinyl chloride, 50 parts of plasticiser, 5 partsof Durcal calcium carbonate filler and 2 parts of LZB 320 stabiliser.

In a further embodiment, the invention provides roofing, tarpaulins,tents, films, sheeting, floor covering, shoes and automobile interiorsobtained from a plasticised polyvinyl chloride composition containingfrom 20 to 100 parts by weight preferably 30 to 90 parts by weight, morepreferably 40 to 80 parts by weight, more preferably 50 to 70 parts byweight of a plasticiser composition containing one or more cyclohexanepolycarboxylic acid esters per 100 parts of polyvinyl chloride.

One widespread use of polyvinyl chloride is as a plastisol. A plastisolis a fluid or a paste consisting of a mixture of polyvinyl chloride anda plasticiser optionally containing various additives. A plastisol isused to produce layers of polyvinyl chloride which are then fused toproduce coherent articles of flexible polyvinyl chloride. Plastisols areuseful in the production of flooring, tents, tarpaulins, coated fabricssuch as automobile upholstery, in car underbody coatings, in mouldingsand other consumer products. Plastisols are also used in medical usessuch as blood bags and tubing, footwear, fabric coating, toys, flooringproducts and wallpaper. Plastisols typically contain 40 to 200 parts byweight, more typically 50 to 150 parts by weight, more typically 70 to120 parts by weight, more typically 90 to 110 parts by weight ofplasticiser per 100 parts of polyvinyl chloride.

Plastisols are usually made from polyvinyl chloride that has beenproduced by emulsion polymerisation or micro suspension polymerisation.The plastisol may be produced by the manufacturer of the polyvinylchloride or a compounder and shipped to the user in fluid form.Alternatively the plastisol may be produced by the user. In eitherinstance, although particularly when the plastisol is produced by themanufacture of the polyvinyl chloride or a compounder, it is importantthat the plastisol viscosity be stable over time.

Phthalate esters are widely used as plasticisers in plastisols. However,plastisols based on phthalate ester plasticisers suffer from thedisadvantages that the viscosity of the plastisol can be undesirablyhigh and that the viscosity of the plastisol can increase to anundesirable extent over time. We have found that when the cyclohexanepolycarboxylic acid esters are used as the plasticiser the plastisolsalso have improved viscosity stability over time, furthermore they alsohave improved viscosity. This is particularly useful where the plastisolis to be stored for sometime between production and use, for examplewhen it is used in coating applications.

The present invention therefore provides a plastisol compositioncontaining from 40 to 200 parts by weight preferably 50 to 150 parts byweight, more preferably 70 to 120 parts by weight, more preferably 90 to110 parts by weight of plasticiser per 100 parts of polyvinyl chloride,wherein the plasticiser comprises one or more cyclohexane polycarboxylicacid esters.

In a further embodiment, the present invention provides a process forthe production of flexible polyvinyl chloride comprising forming a layerfrom a plastisol containing from 40 to 200 parts by weight preferably 50to 150 parts by weight, more preferably 70 to 120 parts by weight, morepreferably 90 to 110 parts by weight of a plasticiser compositioncontaining one or more cyclohexane polycarboxylic acid esters per 100parts by weight of polyvinyl chloride and subsequently fusing the layerby the application of heat.

The use of the esters of cyclohexane polycarboxylic acids asplasticisers for polyvinyl chloride compositions also provides improvedcold flex properties. Cold flex leads to an improved service temperaturerange and is particularly useful in the production of articles used in awide range of temperatures. Throughout this application the cold flexproperties are measured using the Clash and Berg test (ASTM D 1043-84)and the ASTM D 746 brittleness test. The improved cold flex isparticularly useful when the plasticised polyvinyl chloride compositionis to be used in articles which are used over a wide temperature range.In particular this is useful in applications such as roofing, tarpaulinsand tents, protective films including food wrap films, wire and cable,coated fabrics, shoes and medical applications such as blood bags andtubing.

The present invention therefore provides a plasticised polyvinylchloride composition containing from 20 to 100 parts by weightpreferably 30 to 90 parts by weight, more preferably 40 to 80 parts byweight, more preferably 50 to 70 parts by weight of a plasticisercomposition containing one or more cyclohexane polycarboxylic acidesters per 100 parts of polyvinyl chloride having a cold flex below −20°C. as measured by the Clash and Berg test on a formulation of 100 partsof Solvic 271 GC polyvinyl chloride, 150 parts of plasticiser, 80 partsof calcium carbonate filler EXH 1 SP from Omya, 6 parts of Tribasic leadstearate and 1 part of dibasic lead searate.

The workability of these plastisols still leaves something to be desiredand for applications, such as flexible floor coverings it is usual toinclude additives which will depress the viscosity of the plastisol toan even lower level than that achieved by using only conventionalplasticisers. Lower levels of viscosity are commonly achieved by theinclusion of viscosity depressants which are often hydrocarbon fluidssuch as dodecyl benzene (DDB) such as Jayflex 602. However thesematerials are increasingly regarded as unacceptable, particularly inapplications such as floor coverings, because the finished articlesrelease noticeable amounts of volatile materials when they are stored orare in use at room temperature.

The problem of increased emissions is exacerbated in applications suchas floor coverings which are laminates of several layers of polyvinylchloride because it is desirable to minimise the amount of plasticiserpresent in the top coating of the floor covering to improve the wearingproperties and stain resistance. For ease of processing it is thennecessary to use a high level of viscosity depressant. It wouldtherefore be highly desirable to be able to reduce the viscosity of theplastisol during processing without encountering the problem ofincreasing the emissions of volatile organic compounds from the finishedarticles.

Viscosity control is important in the conversion of these plastisolsinto useful products. For example in the preparation of vinyl floorcoverings, the plastisol is spread on a surface moving at around 15 to25 meters per minute in several layers so that the floor covering isliterally built up. Typically these layers include a foam core, adecorative layer and a clear protective wear layer. The multilayerproducts are first gelled by contact with a heated roll and then passedinto an oven where they are fused (gelled) at a temperature of from 180°C. to 200° C. Often the gelling is performed after the spreading of eachindividual layer, starting with the base or encapsulation layer. Afterthe gelling, the next layer can be spread. When all layers have beenspread, the product is then passed into an oven to obtain full fusion ofall layers together and adequate expansion of the foamed layers.

To fulfill the plastisol spread coating requirements in terms ofproduction speed (adequate viscosity and adequate gelation) a wide rangeof viscosity regulators, usually viscosity depressants, are used.

Traditional viscosity depressants used today include hydrocarbon fluids,such as Jayflex 615 or Exxsol D100, dodecyl benzene such as Jayflex 602,sold by ExxonMobil Chemical and 2,2,4-trimethylpentanedioldiisobutyrate, sold as Texanol by Eastman Chemical or specialty estersbased on oleates and laurates. WO 97/35060 discloses a plastisolcomposition comprising a chlorine-containing resin, a primaryplasticiser and a C₁₁–C₁₄ straight chain or branched chain alkylbenzoate.

Although the above products perform well they have limited compatibility(only useful at low concentrations). They also have high volatility, andtheir effect on gelation temperature, their little or no plasticisingeffect, their slow fusion with the resin, their cost performance ratioand their contribution to the VOCs emissions from finished products haslead to a search for improved products.

We have now found that the esters of cyclohexane carboxylic acids may beused as viscosity depressants for plastisols particularly plastisolsusing phthalates as the plasticiser. In a further embodiment theinvention therefore provides the use of an ester of a cyclohexanecarboxylic acid as a viscosity depressant for plastisols.

In yet a further embodiment the invention provides a plasticisedpolyvinyl chloride composition comprising polyvinyl chloride and from 20to 200 preferably 40 to 180, more preferably 60 to 160, more preferably80 to 140, more preferably 100 to 120 parts per 100 parts of polyvinylchloride of a plasticiser composition comprising a plasticiser otherthan an ester of a cyclohexane carboxylic acid ester and an ester of acyclohexane carboxylic acid wherein the amount of cyclohexane carboxylicacid ester present is greater than 5 wt % of the total plasticisercontent.

We have found that levels above 5 wt % of the ester of cyclohexanecarboxylic acid provides a significant reduction in viscosity of theplasticiser composition. We prefer to use from, 5 to 50 wt % of theester of the cyclohexane carboxylic acid, more preferably from 7 to 30wt %, more preferably from 10 to 20 wt % based on the total weight ofplasticiser.

In a preferred system 5 to 20, preferably 7 to 15, more preferably 10 to15 wt % of total phthalate of the lower viscosity esters ofcyclohexanoic polycarboxylic acids particularly diisoheptyl cyclohexanedicarboxylic acid may be used to replace traditional viscositydepressants used in phthalate based formulations such as dodecylbenzene. The use of the ester of cyclohexane polycarboxylic acid willhave the added benefit that the ester will also have a plasticisingeffect.

Where the ester of a cyclohexane mono-carboxylic acid is to be used inconjunction with a primary plasticiser to act as a viscosity depressantthe primary plasticisers may be any of those conventionally used forplasticising chlorine containing resins. These include dialkyl esters ofphthalic anhydrides and cycloalkane dicarboxylic acids with monohydricalcohols having from 4 to 13 carbon atoms, dibenzoate esters, alkylesters of aromatic tri- or tetra-carboxylic acids and aliphaticdicarboxylic acid with monohydric alcohols having 3 to 12, preferably 3to 10, carbon atoms.

Examples of suitable benzenepolycarboxylic acids or a derivativesthereof with which the esters of the cyclohexane carboxylic acids may beused are the alkyl terephthalates such as monomethyl terephthalate,dimethyl terephthalate, diethyl terephthalate, di-n-propylterephthalate, di-n-butyl terephthalate, di-tert-butyl terephthalate,diisobutyl terephthalate, monoglycol esters of terephthalic acid,diglycol esters of terephthalic acid, di-n-octyl terephthalate,diisooctyl terephthalate, mono-2-ethylhexyl terephthalate,di-2-ethylhexyl terephthalate, di-n-nonyl terephthalate, diisononylterephthalate, di-n-decyl terephthalate, di-n-undecyl terephthalate,diisodecyl terephthalate, diisododecyl terephthalate, di-n-octadecylterephthalate, diisooctadecyl terephthalate, di-n-eicosyl terephthalate,monocyclohexyl terephthalate and or dicyclohexyl terephthalate.

Another suitable class are the alkyl phthalates such as monomethylphthalate, dimethyl phthalate, diethyl phthalate, di-n-propyl phthalate,di-n-butyl phthalate, di-tert-butyl phthalate, diisobutyl phthalate,monoglycol esters of phthalic acid, diglycol esters of phthalic acid,di-n-octyl phthalate, diisooctyl phthalate, di-2-ethylhexyl phthalate,di-n-nonyl phthalate, diisononyl phthalate, di-n-decyl phthalate,diisodecyl phthalate, di-n-undecyl phthalate, diisododecyl phthalate,di-n-octadecyl phthalate, diisooctadecyl phthalate, di-n-eicosylphthalate, monocyclohexyl phthalate, dicyclohexyl phthalate; alkylisophthalates such as monomethyl isophthalate, dimethyl isophthalate,diethyl isophthalate, di-n-propyl isophthalate, di-n-butyl isophthalate,di-tert-butyl isophthalate, diisobutyl isophthalate, monoglycol estersof isophthalic acid, diglycol esters of isophthalic acid, di-n-octylisophthalate, diisooctyl isophthalate, di-2-ethylhexyl isophthalate,di-n-nonyl isophthalate, diisononyl isophthalate, di-n-decylisophthalate, diisodecyl isophthalate, di-n-undecyl isophthalate,diisododecyl isophthalate, di-n-octadecyl isophthalate, diisooctadecylisophthalate, di-n-eicosyl isophthalate, monocyclohexyl isophthalate andor dicyclohexyl isophthalate.

Further examples of commercially benzenepolycarboxylic acid esters withwhich the esters of the cyclohexane carboxylic acids may be used includephthalates such as: Palatinol® AH (Di-(2-ethylhexyl) phthalate;Palatinol® AH L (Di-(2-ethylhexyl) phthalate); Palatinol® C (Dibutylphthalate); Palatinol® IC (Diisobutyl phthalate); Palatinol® N(Diisononyl phthalate); Palatinol® Z (Diisodecyl phthalate) Palatinol®10-P (Di-(2-Propylheptyl)phthalate); Palatinol® 711P (Heptylundecylphthalate); Palatinol® 911 (Nonylundecyl phthalate); Palatinol® 11P-E(Diundecyl phthalate); Palatinol® M (Dimethyl phthalate); Palatinol® A(Diethyl phthalate); Palatinol® A (R) (Diethyl phthalate); andPalatinol® K (Dibutylglycol phthalate). Further examples are thecommercially available adipates such as: Plastomoll® DOA(Di-(2-ethylhexyl) adipate) and Plastomoll® DNA (Diisononyl adipate).

In one embodiment the invention therefore provides a plastisol of lowviscosity which can be used to produce finished articles with lowemissions of volatile organic compounds. The composition also providesadditional unexpected benefits during processing and to the propertiesof articles fabricated from the composition. The performance of theester of a cyclohexane mono-carboxylic acid when used in the mixture ofresin and primary plasticiser is surprising in the light of conventionalwisdom as to the theory pertaining to useful non-exuding plasticisers.The compatibility of plasticisers with PVC (and their non-exudingbehaviour) is usually attributed to the presence of diester or triestergroups in the plasticisers, or to the combined presence of an estergroup and at least one aromatic ring.

We have also found that the use of cyclohexane polycarboxylic acidesters as plasticisers for polyvinyl chloride also results in improvedprocessability of the polyvinyl chloride compositions. This improvedprocessability is particularly useful in the transformation of theplasticised polyvinyl chloride composition. Transformations include, forexample, pelletising, extrusion, injection moulding and calendering.Calendering is used in applications such as the production of roofing,protective films including stationery. Extrusion is used in theproduction of films, pipes, guttering and wire and cable coatings.Injection moulding is used in the production of shoes, toys and thelike.

The present invention therefore further provides the use of from 20 to100 parts preferably from 30 to 90, more preferably from 40 to 80, morepreferably from 50 to 70 by weight of a plasticiser compositioncontaining one or more cyclohexane polycarboxylic acid esters per 100parts of polyvinyl chloride to improve the processability of a polyvinylchloride formulation.

In a further embodiment the present invention provides a plasticisedpolyvinyl chloride composition for use in pelletising, extrusion,injection moulding or calendering containing from 20 to 100 partspreferably from 30 to 90, more preferably from 40 to 80, more preferablyfrom 50 to 70 by weight of a plasticiser composition containing one ormore cyclohexane polycarboxylic acid esters per 100 parts by weight ofpolyvinyl chloride.

In a further embodiment the invention provides extruded articlesobtained from a plasticised polyvinyl chloride composition containingfrom 20 to 100, preferably from 30 to 90, more preferably from 40 to 80,more preferably from 50 to 70 parts by weight of a plasticisercomposition containing one or more cyclohexane polycarboxylic acidesters per 100 parts of polyvinyl chloride.

In a further embodiment the invention provides pellets comprisingpolyvinyl chloride and from 10 to 100, preferably from 30 to 90, morepreferably from 40 to 80, more preferably from 50 to 70 parts by weightof a plasticiser composition containing one or more cyclohexanepolycarboxylic acid esters per 100 parts of polyvinyl chloride.

In a further embodiment the invention provides injection mouldedarticles obtained from a plasticised polyvinyl chloride compositioncontaining from 20 to 100, preferably from 30 to 90, more preferablyfrom 40 to 80, more preferably from 50 to 70 parts by weight ofcyclohexane polycarboxylic acid esters per 100 parts of polyvinylchloride.

In a further embodiment the invention provides articles obtained bycalendering a plasticised polyvinyl chloride composition containing from20 to 100, preferably from 30 to 90, more preferably from 40 to 80, morepreferably from 50 to 70 parts by weight of a plasticiser compositioncontaining one or more cyclohexane polycarboxylic acid esters per 100parts by weight of polyvinyl chloride.

We have also found that if esters of cyclohexane polycarboxylic acidsare used as plasticisers in one of adjacent layers of plasticisedpolyvinyl chloride and phthalate plasticisers particularly di-2 ethylhexyl phthalate are used as plasticiser in the other adjacent layer, themigration of the plasticiser from one layer to the other is reduced ascompared with adjacent foils, which contain different of differingamounts of phthalate plasticiser. Undesirably high levels of migrationcan lead to unsightly crinkling of the multi layer foil.

Accordingly, in a further embodiment the present invention provides amultilayer article in which at least two adjacent layers compriseplasticised polyvinyl chloride wherein the plasticiser in one of saidtwo adjacent layers contains an ester of a cyclohexane polycarboxylicacid.

In a further embodiment, the invention provides the use of any one ofthe cyclohexane polycarboxylic acid esters mentioned herein as aplasticiser for polyvinyl chloride to reduce the migration ofplasticiser between adjacent layers of plasticised polyvinyl chloride atleast one of which contains a phthalate ester, particularly di-2 ethylhexyl phthalate as plasticiser.

Another disadvantage of the currently used flexible polyvinyl chloridecontaining phthalates as plasticisers is occurring during incinerationand accidental fires. Due to the high content of the (aromatic)phthalates a heavy smoke generation can be observed during incineration.We have now found that cyclohexane polycarboxylic acid esters impart areduced tendency to form smoke on burning when used as plasticisers inpolyvinyl chloride compositions. This is particularly useful when theplasticised polyvinyl chloride composition is to be incinerated or isaccidentally burnt. Accordingly the use of cyclohexanoates instead ofthe currently used phthalates can provide products with an improvedsafety aspect during incineration and accidental fires.

As stated previously as well as the more favourable burning properties,use of the cyclohexanoates also provides a better low temperatureflexibility and a lower viscosity than the corresponding phthalates.This will enhance the final product properties by providing a broaderapplication temperature range and easier processing if used in plastisolapplications.

The use of esters of cyclohexane polycarboxylic acids as plasticisersfor polyvinyl chloride can result in an increase in the temperaturerequired for gelation compared to compositions based on comparablephthalates. Accordingly in a further embodiment of the invention fastfusing plasticisers can be added to the composition containing the esterof the cyclohexane polycarboxylic acid.

In plastisol applications where the esters of cyclohexane dicarboxylicacids such as diisononyl cyclohexanoic acid (DINCH) could be using suchas wall coverings, flooring, toys, conveyor belts, synthetic leather.Typical formulations could be, in parts by weight

PVC 100 Fast fusing plasticiser  5–25 DINCH 30–50 Filler  0–50stabilizer 1–4 other  0–10

Alternatively typical formulations for use in the production ofautomotive underbody sealants which typically have high plasticiser andhigh filler could be in parts by weight

PVC 100 or PVC copolymer 100 (or combinations of the two)

Fast fusing plasticiser 20–35 DINCH 60–90 Filler such as calciumcarbonate  80–150 stabilizer and other additives  0–10

As a further embodiment formulations for the production of calenderedfloor tiles could be in parts by weight

PVC copolymer 100 or PVC 100 or combinations of the two.

Plasticiser fast fusing 10–30 DINCH 20–30 Epoxidized soybean oil 0–6Filler 500–800 (CaCO3)pigments, stabilizers, other additives 0–10 or as needed

Similar formulations to those set out above could be used but based onother esters of cyclohexane dicarboxylic acid.

Thick extruded materials would also benefit from the addition of a fastfusing plasticiser. Applications include the thick chair mats, waterstops, and extruded profiles. For applications where the extrudedmaterial may be thicker than 3–4 mm, if the plasticised PVC is notthoroughly mixed in the extruder, the surface is blemished, sometimesdull, sometimes containing mold marks, waves, or streaks. Adding alittle fast fusing plasticiser to the plasticiser blend can correct thisproblem. Examples of suitable formulations for extrusions in parts perhundred are

PVC 100 fast fusing plasticiser 5–15 DINCH 10–30  Filler 0–25together with pigments, lubricants, stabilizers, other additives, asneeded.

Hereagain similar formulations based on other esters of cyclohexanedicarboxylic acids could be used.

Examples of non-phthalate fast fusing plasticisers which can be usedinclude diethylene glycol dibenzoate, butyl benzyl phthalate,dipropylene glycol dibenzoate, such as the phenyl cresyl esters ofpentadecyl sulfonic aromatic sulfonic acid esters available from Bayeras Mesamoll, citrates such as tributylacetyl citrate, tri-2-ethylhexylphosphate, trioctyl phosphate such as 2-ethylhexyl-isodecyl phosphate,di-2-ethylhexyl phenyl phosphate, triphenyl phosphate, tricresylphosphate.

High chlorine content chlorinated paraffins are also known to reducefusion and fluxing temperatures. Material containing 60 to 70 wt %chlorine can have fusion temps between 75–84° C. while the lowerchlorine materials, containing 40 to 54 wt % chlorine, can have fluxingtemperatures around 120–135° C.

Low molecular weight diesters such as dibutyl adipate also reducefusion/flux temperatures although we prefer to use no more than 10 phrof those materials because larger amounts could create an undesirablerise in volatility.

In the embodiments of the present invention reference to systemscontaining the esters of the cyclohexane carboxylic acids are to systemsin which the ester of the cyclohexane carboxylic acid is the soleplasticiser and also to systems in which it is present in admixture withother plasticisers.

Polyvinyl chloride is available in many different forms—the variationsbeing in the molecular weight of the polymer, the molecular weightdistribution of the polymer, the particle size of the polymer particles,the particle size distribution and the surface aspect of the particleswhich may be coarse or smooth. Another variable in polyvinyl chloride isthe degree of chain branching. The vinyl polymer may be a copolymer(e.g. a copolymer of vinyl chloride and vinyl acetate). Polymers ofvinyl chloride may be obtained by suspension polymerisation or emulsionpolymerisation. In suspension polymerisation, vinyl chloride monomer issuspended in water with agitation under carefully controlled temperatureand pressure. The batch will also contain suspending agents andinitiators. After polymerisation is complete, the batch is discharged toa stripper where unreacted monomer is removed. Finally, the suspensionis washed and dried to obtain the suspension polyvinyl chloride.

Typical suspension polymerised polyvinyl chloride consists ofagglomerated particles of size in the range 80 to 200 microns. Polyvinylchloride produced by suspension polymerisation is typically used in dryblend applications. Emulsion polymerised polyvinyl chloride is producedin a similar manner to suspension polyvinyl chloride except that thevinyl chloride monomer is emulsified in water so that the polymerisationresults in latex particles. The ratio of water to vinyl chloride monomerin emulsion polymerisation is greater than the ratio of water to vinylchloride monomer in suspension polymerisation. Emulsion polymerisedpolyvinyl chloride also consists of agglomerated particles but theparticles are generally smaller than the particles of suspensionpolymerised polyvinyl chloride. Typically, the agglomerated particles ofemulsion polyvinyl chloride have a particle size in the range of 15 to20 microns. Emulsion polymerised polyvinyl chloride is generally used inthe production of plastisols which are used in coating operations wherethe plastisol is coated onto a substrate and is then fused by heating.

Polyvinyl chloride of particle size between 1 and 40 microns may beproduced by micro suspension polymerisation.

Different forms of polyvinyl chloride are used in differentapplications. One important property is the mean molecular weight of thepolymer. A factor known as the K value is used to indicate the meanmolecular weight of polyvinyl chloride. The K value is the viscosity ofa 0.005 wt % solution of the polyvinyl chloride in cyclohexanone at 25°C. as measured using an Ubbelhode viscometer. The K value is the Germanstandard DIN 53726. The K value of the polyvinyl chloride impacts thefusion temperature and gellation rate of the plasticised polyvinylchloride composition. The K value also influences the melt viscosity ofthe plasticised polyvinyl chloride composition and the rate at which thecomposition can be foamed. Typically the higher the K value the betterthe mechanical properties but the lower the flowability. Accordingly,the formulator of polyvinyl chloride will select the nature of thepolyvinyl chloride and the nature of the plasticiser to optimise theproperties for a particular use.

Where plasticised polyvinyl chloride is to be used in calenderingoperations, it is preferred to use a suspension polymerised polyvinylchloride having a K value in the range 65 to 70. Where the plasticisedpolyvinyl chloride is to be used in wire and cable applications, it ispreferred to use a suspension polymerised polyvinyl chloride having a Kvalue above 70. For injection moulding, a polyvinyl chloride having a Kvalue of 60 to 67 is preferred. Emulsion polymerised polyvinyl chlorideis preferred for applications where good flow of the plasticisedpolyvinyl chloride is required such as spread coating, as used in themanufacture of flooring, chemical foaming, dip coating and rotationalmoulding. For spread coating an emulsion polyvinyl chloride of K value65 to 75 is preferred and for chemical foaming, dip-coating androtational moulding a K value of 65 to 70 is preferred.

The plasticisers used in the present invention are esters of cyclohexanepolycarboxylic acids. The cyclohexane polycarboxylic acids may be the1,2 dicarboxylic acids, the 1,3 dicarboxylic acids or the 1,4dicarboxylic acids. Alternatively, the plasticisers may be esters of thetricarboxylic acids such as 1,3,5, 1,2,3 and 1,2,4 tricarboxylic acids.Mixtures of these acids may also be used. Any alcohol may be used toesterify the acids although it is preferred to use alcohols containingfrom 5 to 20 carbon atoms in particular alcohols containing from 8 to 12carbon atoms are preferred.

The Hexamoll DINCH product recently introduced by BASF is an example ofa cyclohexane dicarboxylic acid ester which can be used in the presentinvention. U.S. Pat. No. 6,284,917 to BASF provides an illustration ofone method by which these materials may be prepared.

Examples of cyclohexane carboxylic acid esters which may be used in thevarious embodiments of the present invention include 1,2-cyclohexanedicarboxylic acid diisobutyl, 1,2-cyclohexane dicarboxylic aciddicyclohexyl, 1,2-cyclohexane dicarboxylic acid diiso heptyl,1,2-cyclohexane dicarboxylic acid di (3,5,5-trimethyl hexyl),1,2-cyclohexane dicarboxylic acid di (2,6-di methyl-4-heptyl),1,2-cyclohexane dicarboxylic acid diisodecyl, 1,2-cyclohexanedicarboxylic acid diisoundecyl, 1,2-cyclohexane dicarboxylic acid diisotridecyl, 1,2-cyclohexane dicarboxylic acid diiso octadecyl, diisooctadecyl, 3-methyl-1,2-cyclohexane dicarboxylic acid diisobutyl,3-methyl-1,2-cyclohexane dicarboxylic acid dicyclohexyl,3-methyl-1,2-cyclohexane dicarboxylic acid diiso heptyl,3-methyl-1,2-cyclohexane dicarboxylic acid di (2-ethylhexyl),3-methyl-1,2-cyclohexane dicarboxylic acid di (3,5,5-trimethyl hexyl),3-methyl-1,2-cyclohexane dicarboxylic acid di (2,6-di methyl4-heptyl),3-methyl-1,2-cyclohexane dicarboxylic acid diisodecyl,3-methyl-1,2-cyclohexane dicarboxylic acid diisoundecyl,3-methyl-1,2-cyclohexane dicarboxylic acid diiso tridecyl,3-methyl-1,2-cyclohexane dicarboxylic acid diiso octadecyl,4-methyl-1,2-cyclohexane dicarboxylic acid diisobutyl,4-methyl-1,2-cyclohexane dicarboxylic acid dicyclohexyl,4-methyl-1,2-cyclohexane dicarboxylic acid diiso heptyl,4-methyl-1,2-cyclohexane dicarboxylic acid di (3,5,5-trimethyl hexyl),4-methyl-1,2-cyclohexane dicarboxylic acid di (2,6-di methyl-4-heptyl),4-methyl-1,2-cyclohexane dicarboxylic acid diisodecyl,4-methyl-1,2-cyclohexane dicarboxylic acid diisoundecyl,4-methyl-1,2-cyclohexane dicarboxylic acid diiso tridecyl,4-methyl-1,2-cyclohexane dicarboxylic acid diiso octadecyl.

Cyclohexane polycarboxylic acid straight chain alkyl ester, usually,jointly using with one, two or more kinds of the aforementionedalicyclic polycarboxylic acid branched alkyl ester and/or cycloalkylester may also be used.

Examples of the straight chain alkyl ester include 1,2-cyclohexanedicarboxylic acid di heptyl, 1,2-cyclohexane dicarboxylic acid dioctyl,1,2-cyclohexane dicarboxylic acid di decyl, 1,2-cyclohexane dicarboxylicacid di undecyl, 1,2-cyclohexane dicarboxylic acid di dodecyl,1,2-cyclohexane dicarboxylic acid di tetradecyl, 1,2-cyclohexanedicarboxylic acid dihexadecyl, 1,2-cyclohexane dicarboxylic aciddioctadecyl, 3-methyl-1,2-cyclohexane dicarboxylic acid di heptyl,3-methyl-1,2-cyclohexane dicarboxylic acid dioctyl,3-methyl-1,2-cyclohexane dicarboxylic acid di decyl,3-methyl-1,2-cyclohexane dicarboxylic acid di undecyl,3-methyl-1,2-cyclohexane dicarboxylic acid di dodecyl,3-methyl-1,2-cyclohexane dicarboxylic acid di tetradecyl,3-methyl-1,2-cyclohexane dicarboxylic acid dihexadecyl,3-methyl-1,2-cyclohexane dicarboxylic acid dioctadecyl,4-methyl-1,2-cyclohexane dicarboxylic acid di heptyl,4-methyl-1,2-cyclohexane dicarboxylic acid dioctyl,4-methyl-1,2-cyclohexane dicarboxylic acid di decyl,4-methyl-1,2-cyclohexane dicarboxylic acid di undecyl,4-methyl-1,2-cyclohexane dicarboxylic acid di dodecyl,4-methyl-1,2-cydohexane dicarboxylic acid di tetradecyl,4-methyl-1,2-cyclohexane dicarboxylic acid dihexadecyl,4-methyl-1,2-cyclohexane dicarboxylic acid dioctadecyl.

Other cyclohexane carboxylic acid esters include those derived fromphthalates and in particular the following: cyclohexane-1,2-dicarboxylicacid di(isopentyl) ester, obtainable by hydrogenation of adi(isopentyl)phthalate having the Chemical Abstracts registry number (inthe following: CAS No.) 84777-06-0; cyclohexane-1,2-dicarboxylic aciddi(isoheptyl) ester, obtainable by hydrogenating thedi(isoheptyl)phthalate having the CAS No. 71888-89-6;cyclohexane-1,2-dicarboxylic acid di(isononyl) ester, obtainable byhydrogenating the di(isononyl)phthalate having the CAS No. 6851548-0;cyclohexane-1,2-dicarboxylic acid di(isononyl) ester, obtainable byhydrogenating the di(isononyl)phthalate having the CAS No. 28553-12-0,which is based on n-butene; cyclohexane-1,2-dicarboxylic aciddi(isononyl) ester, obtainable by hydrogenating thedi(isononyl)phthalate having the CAS No. 28553-12-0, which is based onisobutene; a 1,2-di-C₉-ester of cyclohexane dicarboxylic acid,obtainable by hydrogenating the di(nonyl)phthalate having the CAS No.68515-46-8; cyclohexane-1,2-dicarboxylic acid di(isodecyl) ester,obtainable by hydrogenating a di(isodecyl)phthalate having the CAS No.6851549-1; 1,2-C₇₋₁₁-ester of cyclohexane dicarboxylic acid, obtainableby hydrogenating the corresponding phthalic acid ester having the CASNo. 68515-42-4; 1,2-di-C₇₋₁₁-ester of cyclohexane dicarboxylic acid,obtainable by hydrogenating the di-C₇₋₁₁ -phthalates having thefollowing CAS Nos.:111381-89-6, 111381-90-9, 111381-91-0, 68515-44-6,6851545-7 and 3648-20-7; a 1,2-di-C₉₋₁₁ -ester of cyclohexanedicarboxylic acid, obtainable by hydrogenating a di-C₉₋₁₁-phthalatehaving the CAS No. 98515-43-5; a 1,2-di(isodecyl)cyclohexanedicarboxylic acid ester, obtainable by hydrogenating adi(isodecyl)phthalate, consisting essentially ofdi-(2-propylheptyl)phthalate; 1,2-di-C₇₋₉-cyclohexane dicarboxylic acidester, obtainable by hydrogenating the corresponding phthalic acidester, which comprises branched and linear C₇₋₉-alkylester groups;respective phthalic acid esters which may be e.g. used as startingmaterials have the following CAS Nos.: di-C₇₋₉-alkylphthalate having theCAS No. 111 381-89-6; di-C₇-alkylphthalate having the CAS No.68515-44-6; and di-C₉-alkylphthalate having the CAS No. 68515-45-7.

More preferably, the above explicitly mentioned C₅₋₇, C₉, C₁₀, C₇₋₁₁,C₉₋₁₁ and C₇₋₉ esters of 1,2-cyclohexane dicarboxylic acids are thehydrogenation products of the commercially availablebenzenepolycarboxylic acid esters with the trade names Jayflex® DINP(CAS No. 68515-48-0), Jayflex® DIDP (CAS No. 68515-49-1), Palatinole9-P, Vestinol® 9 (CAS No. 28553-12-0), TOTM-I® (CAS No. 3319-31-1),Linplast® 68-TM and Palatinol® N (CAS No. 28553-12-0) which are used asplasticisers in plastics.

A particularly preferred ester comprises a mixture of diesters ofcyclohexanoic dicarboxylic acid with a mixture of alcohols having anaverage carbon number between 8.5 and 9.5 in whose 1H-NMR spectrum,obtained in deuterated choroform (CDCl3), the ratio [R2] of the surfacearea below the resonance signals with chemical shifts in the rangebetween the lowest valley close to 1.0 and 2.0 towards tetramethylsilane(TMS) to the surface area below the resonance signals with chemicalshifts in the range between 0.5 and the lowest valley close to 1.0 ppmtowards TMS is between 1.35 and 5.50.

In the 1H-NMR-measurement used to characterise the alcohols used toproduce the esters a dilute solution of the alcohol in deuteroform isused as the sample and the average carbon number is determined asfollows. The alkyl-protons between 2 and 0.4 ppm are integrated and the—CH2O-protons between 3.9 and 3 ppm are also integrated. The hydroxylproton can be observed between 3 and 2 ppm. With I (n−m ppm)representing the integration of the region between n and m ppm relativeto TMS:

$\text{Average~~carbon~~number} = \frac{\begin{matrix}\left( {{I\left( {2 - {0.4\mspace{14mu}{ppm}}} \right)} +} \right. \\\left. {0.5 \times I\left( {3.9 - {3\mspace{14mu}{ppm}}} \right)} \right)\end{matrix}}{I\left( {3.9 - {3\mspace{14mu}{ppm}}} \right)}$

For the phthalates, the —CH2O-protons of the ester group are seen in theregion between 6 and 3 ppm, typically between 5 and 3.5 ppm. The protonson the aromatic ring are seen before 7.5 ppm and do not influence theintegration. The above formula for the phthalates is therefore asfollows:

$\text{Average~~carbon~~number} = \frac{\begin{matrix}\left( {{I\left( {2 - {0.4\mspace{14mu}{ppm}}} \right)} +} \right. \\{\left. {0.5 \times {I\left( {5 - {3.5\mspace{14mu}{ppm}}} \right)}} \right)/}\end{matrix}}{I\left( {5 - {3.5\mspace{14mu}{ppm}}} \right)}$

The formulae used are based on the stoichiometric formula of a saturatedprimary alcohol. If it has an average carbon number of x, its formula isH—O—CH2—(C(x−1)H(2n−1))

The arithmetic takes the (2n−1) from the alkyl chain excluding the—CH2O-protons, adds 0.5×2=1 from the —CH2O— protons. This sums up to 2nin the numerator. The denominator is the 2 from the —CH2O-protons, and2n/2 makes n, i.e. the average carbon number on the alkyl chain.

For cyclohexanoates, one has to discount the 8 protons on thecyclohexane ring in each molecule, and which are showing up also in therange 1.0–2.0 ppm, amongst the protons of the alkyl chain. This can bedone by substracting from the numerator 2 times the I (5–3.5 ppm), asthere are 8 such protons in the ring against 4—CH2O-protons in eachcyclohexanoate molecule. Hence for cyclohexanoates

$\text{Average~~carbon~~number} = \frac{\begin{matrix}\left( {{I\left( {2 - {0.4\mspace{14mu}{ppm}}} \right)} -} \right. \\{\left. {1.5 \times {I\left( {5 - {3.5\mspace{14mu}{ppm}}} \right)}} \right)/}\end{matrix}}{I\left( {5 - {3.5\mspace{14mu}{ppm}}} \right)}$

In certain embodiments of the invention the cycloalkane plasticisersdescribed herein preferably exclude a 1,2-cyclohexane dicarboxylic aciddiester obtained by esterifying 1,2-cyclohexane dicarboxylic acid andmixed aliphatic monohydric alcohols of from 4 to 13 carbons,characterised in that the above mentioned mixed aliphatic monohydricalcohols comprise from 80 to 97% by weight of C9 branched alcohols andfrom 3 to 20% by weight of alcohols other than C9 branched alcohols.

The esters may be obtained by the esterification of the cyclohexanepolycarboxylic acids or the corresponding anhydrides. Alternatively theymay be prepared by the Diels Alder condensation of butadiene and maleicanhydride followed by hydrogenation and esterification. Another methodby which the esters may be obtained is the hydrogenation of thecorresponding phthalates as is described in PCT Publication WO 99/32427.

The polyvinyl chloride and the ester of the cyclohexane polycarboxylicacid may be mixed by the conventional formulating techniques currentlyused in the production of plasticised polyvinyl chloride formulations.The formulator will attempt to provide a versatile composition having agood balance of properties at reasonable cost. The formulator will beconcerned to optimise the balance between end-product properties such asflexibility, low temperature performance, flame resistance, hightemperature resistance, volatility, stain resistance, electricalproperties and processability and the processing properties such asplastisol viscosity, fusion, dry blending, emissions and printability.

The formulations containing the polyvinyl chloride and the plasticisermay contain other additives. The majority of formulations will contain astabiliser which counters the effects of ageing; heat stabilisers alsoreduce the dehydrodehalogenation of the polyvinyl chloride at thetemperatures at which the formulation is processed. Stabilisers, such asbenzotriazole and benzophenone, also reduce the degradation by sunlight,ozone and biological agents. The improved ultra-violet stabilityobtained by the use of the esters of the cyclohexane polycarboxylicacids according to the present invention may enable smaller amounts ofstabilisers to be used. Typically, the formulations contain from 0.5 to10 parts, normally from 1.5 to 3 parts, by weight of stabiliser per 100parts of the polyvinyl chloride.

Stabilisers to provide stability during heat processing are typicallymetal compounds, particularly lead salts, which are used in wire andcable applications, organotin compounds, barium, cadmin and zinc saltsor calcium/zinc stabilisers. Organic phosphates and polyols may also beused. Lead stabilisers are used in wire and cable applications.Calcium/zinc stabiliser systems are used in wire and cable, foil andsheeting, wall coverings, medical applications, tubes and footwear, foodpackaging film and fabric coating. Barium/zinc stabiliser systems areused in foil and sheeting, flooring, wall covering, tubes and footwearand fabric coating. Tin stabilisers are used in flooring and wallcovering. Zinc compounds are frequently used as a stabiliser and as akicker in formulations used to produce foams in, for example, flooring,wall covering and fabric coating.

Other ingredients which may be added to the polyvinyl chlorideformulations include fillers such as calcium carbonate, titanium dioxideor silica. When used, the filler may be present in an amount up to 150parts, preferably up to 100 parts per 100 parts of polyvinyl chloride.Lubricants, pigments and processing acids may be included. Otheringredients will be chosen according to the use to which the formulationis to be put. For example, the formulation may contain flame retardants,blowing agents and kickers, bio-stabilisers, antistatic agents,viscosity regulators such as thickeners and thinners, antifogging agentswhich are particular useful is packaging films and antioxidants, such asbisphenol A.

Fillers are incorporated in the formulations to reduce cost, increasethe output of dry blending, increase electrical resistance, increaseresistance to ultra-violet light, increase hardness, produce improvedheat transmission, increase the resistance to heat deformation. Fillerscan also impart anti-blocking or anti-slip performance. Examples ofsuitable fillers include calcium carbonate, clays such asalumino-silicates, silica, dolomite and bauxite.

The particular particle size distribution and average surface area ofthe filler will be chosen according to the properties it is desired toimpart.

Lubricants and processing aids may be included to reduce the adhesionbetween polyvinyl chloride and hot machinery surfaces during processing.The lubricants also affect the frictional properties between resinparticles during processing. Examples of lubricants include stearic acidand metal stearates which can also act as stabilisers.

Other lubricants that may be used include petroleum waxes, silicon oil,mineral oil, synthetic oils and polyethylene waxes.

The formulations may also contain flame retardants to increase ignitiontime, reduce flame spreading and rate of burning. The flame retardantsshould have a high decomposition temperature, low volatility, a minimumeffect on thermal and mechanical properties and good resistance to lightand ultra-violet radiation. Examples of flame retardants that may beused include halogen containing compounds and phosphorous containingorganic compounds such as triaryl, trialkyl or alkyl diaryl phosphateesters. Other materials that may be used include chloroparaffins,aluminum trihydrate Al(OH)₃ or antimony oxides Sb₂O₃.

Where the formulations are used to produce foams such as in flooringmaterials, they can contain a blowing agent which decomposes with theevolution of gas bubbles during processing of the plastisol. Examples ofsuitable blowing agents include azodicarbonamide which releases nitrogenwhen heated to a temperature in the range 200° C. to 250° C. The systemmay also contain kickers which control and lower the decompositiontemperature of the blowing agent. For example lead compounds such asdibasic lead phthalate, zinc oxide or barium/cadmium compounds may beused to reduce the activation temperature of azodicarbonamide to atemperature in the range 150° C. to 215° C. These metal compounds canalso act as stabilisers.

The present invention is illustrated by the following examples in whichthe C₇, C₈, C₉ and C₁₀ esters of bis-1.2-cydohexanedicarboxylicanhydride were prepared using the commercial C₇ alcohol available fromExxonMobil Chemical Exxal 7 to produce the C₇ ester (DIHCH), 2 ethylhexanol to produce the C₈ ester (DEHCH), the commercial C₈ alcoholavailable as Exxal 8 from ExxonMobil Chemical to produce C₈ ester(DIOCH), the commercial C₉ alcohol available from ExxonMobil Chemical asExxal 9 to produce the C₉ ester (DINCH) and the commercial C₁₀ alcoholavailable from ExxonMobil Chemical as Exxal 10 to produce the C₁₀ ester(DIDCH). A standard esterification procedure using a titanium catalystwas used such as is described in the Encyclopedia of ChemicalTechnology, Jaqueleine I Kroschwitz, Mary Howe-Grant, fourth edition,vol 9 pages 755–780 by John Wiley and Sons. For ease of reference thematerials are referred to as cyclohexanoic esters.

The reaction therefore proceeds as follows.

The properties of the materials were measured using the test methods setout in Table 1 and were found to be as shown in Table 1:

TABLE 1 Property Method Unit DIHCH DEHCH DINCH DIDCH Vis- ASTM mPa * s34.0 45.5 64.7 87.0 cosity @ D445 20° C. Density @ ASTM g/cm³ 0.9610.955 0.946 0.943 20° C. D4052 Water ASTM E ppm 154 64 111 69 content1064 Acid value ASTM mg/g 0.11 0.03 0.03 0.04 D1045 KOH

The properties of the cyclohexanoic esters were compared to those of thecorresponding phthalates made with the same alcohols, di-2-ethyl hexylphthalate (DEHP); di-isoheptyl phthalate (Jayflex 77); di-isononylphthalate (DINP) and di-isodecyl phthalate (DIDP).

FIG. 1 plots the viscosity and density of the different esters againstthe carbon number of the alcohol used to make the ester. FIG. 1 showsthat the viscosity of the cyclohexanoic ester is below that of thecorresponding phthalate. This will lead to a lower viscosity ofplastisols based on the cyclohexanoic esters and therefore to easierprocessing of the plastisols.

FIG. 1 also shows that the density of the cyclohexanoic ester is belowthe density of the corresponding phthalate. This has the benefit that informulations using the cyclohexanoic ester as plasticiser the volume ofthe same weight of the plasticised polyvinyl chloride is greater than incomparable formulations using the phthalate ester as the plasticiser.This enables more final product to be made from formulations containingless polyvinyl chloride, in addition the lower efficiency of thecyclohexanoate esters reinforces this effect.

EXAMPLE 1

The esters as manufactured above were tested as plasticisers in flexiblepolyvinyl chloride.

The products were used as plasticiser in the following plastisolformulations:

SOLVIC 367 NC (Polyvinyl chloride from Solvin) 100 phr  Plasticiser 50phr Durcal 5 (calcium carbonate filler) 10 phr LZB 320 (Lankromark fromAkcros Chemicals)  2 phr

All formulations were prepared at the same plasticiser level.

FIG. 2 shows the relative shore D hardness versus plasticiser content ofthis formulation and also the film and sheet formulation.

FIG. 3 shows the initial viscosities of the plastisols and plots theBrookfield viscosity of the plastisols during storage over a 7 dayperiod. The viscosities were measured with a Brookfield viscometer. FIG.3 shows that the plastisol based on the cyclohexanoic ester have asignificantly lower initial viscosity than the plastisol based on thecorresponding phthalate. FIG. 3 also shows that the stability over timeof the viscosity of the plastisol using the cyclohexanoic ester as theplasticiser was better than the corresponding phthalate based plastisol.This indicated that the cyclohexanoic esters could therefore be used notonly as a primary plasticiser but also as viscosity depressants inplastisol applications. 0.6 mm gauge films were produced from theseplastisol formulations by spread coating plastisols with a knife on arelease paper and heating the coated paper in a Werner Mathis oven at180° C. for 1 minute. The films were then evaluated for hardness,thermal stability and stability to ultra-violet light. Hardness ismeasured according to the DIN 53505 test method which is also ASTM D2240-86.

The hardness was found to be as set out in Table 2.

TABLE 2 Plasticiser J77 DIHCH DOP DEHCH DINP DINCH DIDP DIDCH Shore A78.2 79.3 81.5 81.8 85.0 86.3 86.2 89.1 Shore D 28.3 28.4 31.1 31.5 34.936.0 36.6 38.9

The thermal stability of each film was tested in the Werner Mathisthermo tester at 180° C. (90 sec/cm). The results were as follows.

Formulation 1: DOP   33 min Formulation 2: DEHCH 32.3 min Formulation 3:DINP 28.5 min Formulation 4: DINCH   30 min Formulation 5: DIDP 28.5 minFormulation 6: DIDCH 30.8 min Formulation 7: DIHCH 36.3 min Formulation8: Jayflex 77 38.7 min

These results indicate comparable stability between the cyclohexanoicesters and the phthalates.

The stability of the films to ultra-violet light was tested in a QUV(Cycle: 4 hours UV at 60° C., 4 hours condensation at 50° C.). Lack ofstability is indicated by a darkening of the film samples. Evaluationsof the colouring of the samples were made after 220 hours, 456 hours,626 hours, 794 and 1056 hours of test.

The colour of the samples is shown in the Table 3. It can be seen thatthe darkening over time of the cyclohexanoic esters based formulationswas less than that of the formulations based on the correspondingphthalates.

TABLE 3 Plasticiser DOP DEHCH DINP DINCH DIDP DIDCH Original White WhiteWhite White White White After Pale White Pale White Pale White  220Hours Yellow Yellow Yellow After Yellow White Yellow White Yellow Pale 456 Hours Yellow After Yellow White Yellow White Yellow Yellow  626Hours After Yellow Pale Yellow Pale Yellow Yellow  794 Hours YellowYellow Brown Brown After Dark Yellow Yellow Yellow Yellow Yellow 1056Hours Yellow Brown Brown Brown

After 794 hours the differences between the phthalates and thecyclohexanoic esters start to level off, however, even after that lengthof test the samples containing DEHCH and DINCH were outperforming filmscontaining the corresponding phthalates.

EXAMPLE 2

The following wire and cable coating compounds were prepared.

Solvic 271 GC 100 phr  100 phr  100 phr 100 phr DOP 50 phr 100 phr DEHCH50 phr 100 phr Filler - calcium carbonate 80 phr 80 phr  80 phr  80 phr(EXH1SP from Omya) Tribasic lead stearate  6 phr  6 phr  6 phr  6 phr(Interstab PTS-E from Akcros Chemicals) Dibasic lead stearate  1 phr  1phr  1 phr  1 phr (Interstab P51 from Akcros Chemicals)

Similar compounds were produced containing DINP, DINCH, DIDP and DIDCHas plasticisers. The plasticiser contents were chosen to producematerials of comparable hardness and were as follows

-   -   i. the DINP formulations contained 53 (106) phr plasticiser.    -   ii. the DINCH formulations contained 54.5 (109) phr plasticiser.    -   iii. the DIDP formulations contained 55 (110) phr plasticiser.    -   iv. the DIDCH formulations contained 57.5 (115) phr plasticiser.

The Shore A and Shore D hardness (ASTM D 2240-86) was measured and foundto be as shown in Table 4.

TABLE 4 DOP DEHCH DINP DINCH DIDP DIDCH phr 50 50 53 54.5 55 57.5 ShoreA 90.3 90.9 91.2 91 90.4 91.7 Shore D 38.2 38 38.7 38 38 36.4

Table 4 shows that comparable hardness can be obtained with thecyclohexanoic esters using less polyvinyl chloride.

The low temperature flexibility of the materials was measured using theClash and Berg test (ASTM D 1043-84) and the ASTM D 746 brittleness testand were found to be as set out in Table 5.

TABLE 5 DOP DEHCH DINP DINCH DIDP DIDCH Clash & Berg ° C. −17.0 −20.7−18.1 −26.0 −21.7 −29.7 Brittleness −14.0 −16.2 −16.8 −22.0 −19.6 −26.5

Here the lower Clash and Berg and brittleness temperatures show theimproved low temperature properties of the cyclohexanoic esters.

EXAMPLE 3

Foil and sheeting compounds were prepared according to the followingformulation.

Solvic 271 GC 100 phr  Plasticiser 35 phr Ba/Zn Stabiliser (Lankromark -LZB 722  2 phr from Akcros Chemicals) ESBO (epoxidised soya bean oil -lubricant) 0.5 phr 

The Shore D hardness of the formulations containing various plasticiserswere found to be as shown in Table 6.

TABLE 6 DOP DEHCH DINP DINCH DIDP DIDCH Shore D 47 48.3 51.4 52.7 52.955.2

The mechanical properties were obtained from samples in a Zwick tensiletester measuring the modulus at 100% extension, the stress at break andthe elongation at break. The results are set out in Table 7.

TABLE 7 Modulus at Stress at break Elongation at 100% (N/mm²) (N/mm²)break (%) DOP (50 phr) 10.9 15.6 301 DEHCH (50 phr) 11.4 14.5  223* DINP(53 phr) 10.7 15.1 289 DINCH (54.5 phr) 10.5 14.9 290 DIDP (55 phr) 11.216.0 299 DIDCH (57.5 phr) 10.4 13.5 235

The same mechanical properties were measured on samples that had beenaged at 100° C. for 7 days with natural ventilation and the results areset out in Table 8 which shows the percentage retained properties afterageing in relation to the original data in Table 7.

TABLE 8 Retained Retained Retained Modulus at Stress at break Elongationat 100% (N/mm²) (N/mm²) break (%) DOP (50 phr) 98.6 95.5 90.8 DEHCH (50phr) 95.1 96.2 105.6 DINP (53 phr) 100.7 94.1 87.5 DINCH (54.5 phr)104.4 94.2 84.3 DIDP (55 phr) 107.0 98.5 87.0 DIDCH (57.5 phr) 99.0 96.8100.5

The weight loss of the samples after ageing was measured and found to beas set out in Table 9.

TABLE 9 Weight Loss DOP DEHCH DINP DINCH DIDP DIDCH (mg/cm2) 0.60 1.920.26 0.53 0.21 0.27 % 0.79 2.49 0.35 0.72 0.27 0.38

The weight loss shows DEHCH to have a higher volatility which may limitthe use of DEHCH in wire and cable applications. However, the data showsthat by changing to DINCH or DIDCH this drawback can be overcome.

All of the compounds except the DEHCH based compound passed the Germanwire and cable standards YI4, YI5, YM3 and YM5.

This data shows that in most of the applications DOP, DINP or DIDP canbe substituted by DINCH or DIDCH.

The melt viscosities of the formulations were measured at 170° C. Theresults are shown in FIG. 4.

The formulations show a decreasing melt viscosity in the order:DOP>DEHCH>DINP>DIDP>DINCH>DIDCH showing the easier processability of thesystems using the cyclohexanoic esters as plasticisers leading to ahigher throughput in operations such as extrusion, callending, injectionmoulding and pelletising.

The mechanical properties of these foil and sheeting formulations areshown in FIG. 5.

FIG. 5 shows that whereas by increasing the molecular weight of thephthalate (same level of plasticiser) the elongation at break isdecreasing the opposite effect are achieved with the cyclohexanoicesters. The elongation at break of the cyclohexanoic ester formulationincreases with increasing the molecular weight. The 100% modulus and thestress at break are slightly different using phthalates or cyclohexanoicesters and this difference is diminishing by increasing the molecularweight.

The Clash & Berg Temperatures (° C.) (ASTM D 1043-84) of theseformulations were measured and found to be as set out in Table 10.

TABLE 10 Alcohol Phthalate Cyclohexanoic ester C₈ −6.0 −9.0 C₉ −4.4 −8.1C₁₀ −4.9 −7.7

The Clash & Berg temperature at the same level of plasticiser wastherefore, on average, 3.3° C. lower for the cyclohexanoic esters thancompared to the phthalates.

This indicates improved cold flex performance for the cyclohexanoicester based formulations.

The migration of the plasticisers from the sheets made from theseformulations is measured by a test in which 5 centimeter diameter discsof the plasticised polyvinyl chloride were cut from 0.5 mm thick moldedpads. Sandwiches were prepared from 2 discs containing differentplasticisers. Three piles of five sandwiches were then placed in an ovenheld at 50° C. under a load of 5 kilograms.

The weight change in each disc was measured over several days and theaverage weight change for each sandwich calculated. The calculatedaverage is the average of the weight changes of the two layers in thesandwich, a weight loss is taken as a positive number. The results areshown in FIG. 6. FIG. 6 shows that there is very limited migrationbetween two discs, one of which is plasticised with DOP and the otherplasticised with DEHCH. FIG. 6 also shows that the combination DOP-DINCHmigrates two times slower than the DOP-DIDP. Therefore DEHCH and DINCHare a good substitute for DOP in all applications where migrationbetween flexible PVC parts with different plasticiser plays a role andcan also be used in structures in which one of the layers contains DOP.

The viscosity depressing effect of diisoheptyl cyclohexanoate wasdetermined in formulations containing diisoheptyl phthalate (Jayflex 77)and also dodecyl benzene (DDB), the results are set out in Table 11.

TABLE 11 PVC 100 100 100 100 100 100 BBP 30 — — — — — Jayflex 77 — 40 4030 25 — DIHCH — — 8 10 15 20 DOP 10 — — — — — Jayflex DINP — — — — — 20Tinstab 1 1 1 1 1 1 DDB 8 8 — — — — Σ liquids 48 48 48 40 40 40Brookfield 2 h 7600 3400 5300 23250 19000 12500 Viscosity 4 h 8300 35005550 23500 18750 12800 [mPas] 1 day 11400 4450 7650 31500 25500 17250 5days 14600 5600 10400 44500 37000 23500 HBG [° C.] 58 66 59 59 60 66Volatility (pregelled) 1.87 1.56 0.96 0.97 0.97 0.92 [wt %]**Pregelling: 20 sec at 160° C. airspeed: 1000 rpm; weight loss: 2 min at180° C., airspeed 2300 rpm HBG is the hot bench gellation temperature

The viscosity stability of formulations containing DIHCH as a viscositydepressant was also measured and found to be as set out in Table 12.

TABLE 12 PVC 100 100 100 100 100 100 Jayflex DINP 60 50 30 — 53 30 DIHCH— 10 30 60 — — Jayflex 77 — — — — — 30 LZ 1364 2 2 2 2 2 2 DDB — — — — 7— Brook- 2 h 3550 2900 2200 1400 2150 2750 field 4 h 3600 2950 2300 14502200 2850 vis- 1 day 3750 3050 2300 1600 2250 2950 cosity 4 3700 30502300 1650 2250 3000 [mPas] days HBG [° C.] 101 104 103 102 114 95Volatility 0.14 0.21 0.33 0.52 0.47 0.23 [wt %]* *Weight loss: 2 min at180° C., airspeed 2300 rpm

The results are illustrated graphically in FIG. 7.

The esters of cyclohexane carboxylic acids described herein are alsouseful in liquid systems and in particular as liquid solvents andprocessing acids.

In particular the esters of cyclohexane polycarboxylic acids such as1,2-dicarboxylic acids, the 1,3-dicarboxylic acids or the1,4-dicarboxylic acids. Alternatively they may be esters of thetricarboxylic acids such as 1,3,5, 1,2,3 and 1,2,4-tricarboxylic acids.Mixtures of these acids may also be used. Any alcohol may be used toesterify the acids although it is preferred to use alcohols containingfrom 5 to 20 carbon atoms, in particular alcohols containing from 6 to12, more preferably 6 to 8, carbon atoms are preferred.

In one embodiment the esters previously described herein can be used assolvents in liquid formulations for the handling of agriculturalchemical products because of their lower cost of manufacture and theease of handling. Cyclohexane di-esters of C₂ through C₈ alcohols areparticularly useful in this application. These diesters will findapplication as primary solvents or co-solvents in low volume, ultra-lowvolume or emulsifiable concentrate formulations.

The use of the diesters increase the flexibility of the formulator ofagricultural chemical pesticides because of their broad range ofphysical properties. The diesters have strong and unique solvency. Theyderive their strength from the polarity and hydrogen bonding of theesters while the cycloparaffinic ring provides a dispersive force. Thismeans that the diesters will display affinities for active ingredientsof many chemical types.

Volatility controls the residence time an active ingredient remains onthe surface of a plant or insect. In the case of this family of diestersdescribed herein, the evaporation rate and flash point can be controlledby the choice of the molecular weight of the ester through selection ofthe alcohol from which it is made. Many of these diesters will also meetlow vapour pressure regulatory requirements.

The low pour point properties of these diesters will also allow theiruse as solvents in cold climates.

Many active ingredients are unstable or insoluble in water: the storagestability of active ingredients formulated into emulsifiableconcentrates is dependent on low water solubilities. The diestersdescribed herein also have the desirable low water solubility.

It is also expected that when these diesters are formulated and appliedat realistic levels, they will pose minimal phytotoxic risk.

In another embodiment the esters of cyclohexane carboxylic acidsdescribed herein are used as solvents in carbonless copy paper (CCP)which is made using a micro-encapsulation process. A CCP set consists ofthree sheets of paper, one original and two copies. The top sheet(original) has a plane front and is coated with microcapsules on theback. The middle sheet (1^(st) copy) is coated with a developer on thefront and microcapsules on the back. The bottom sheet (2^(nd) copy) iscoated with a developer on the front and is plain on the back. Themicrocapsules contain colourformers, ‘dyes’, that change colour whenthey come in contact with the developer. Solvents are used as carriersfor the colourformers. Prime solvents are used to dissolve thecolourformers and diluent solvents are used to reduce solutionviscosity. When the microcapsules are broken (pen, printer head etc),the encapsulated colourformer solution comes in contact with thedeveloper, forming an image.

Cyclohexanoic acid diesters, particular the diesters of C₂ through C₆alcohols, are good candidates for prime solvents in CCP. These diestershave the high solvency power needed to dissolve colourformerssufficiently and are compatible with currently marketed diluentsolvents. These diesters have the general requirements for prime anddiluent solvents: high purity, low odour, light stability and theappropriate molecular weight to dry by absorption.

The diesters are compatible with the various compositions of themicrocapsules, typically polyamide, polyurethane, polyvinyl alcohol oracrylic. The diesters are also compatible with the developer layer,typically clay or phenolic resins.

In a further embodiment the esters are of cyclohexane carboxylic acidsdescribed herein also useful as solvents for printing inks generallycontain pigments for coloration, resins to form the ink film, additivesto impart special properties and solvents for viscosity control and tocarry the ingredients to the substrate.

The resins used in the inks are solids or semi-solid organic substanceswhich bind the pigments to the printed surface. An ink varnish orvehicle is made by dissolving resin and additives in solvent. A pigmentflush is pre-dispersed pigment in resin, solvent and additives. Afinished ink typically contains varnish, pigment flush and additionalsolvent and additives.

Paraffin hydrocarbon solvents are commonly used to make a varnish for apaste ink. Examples would be Exx-Print® 283 D and Exx-Print® 588 Dfluids. Co-solvents (TXIB, Exxal® 13) are often added to the varnish toimprove resin-solvent compatibility, reduce tack or adjust viscosity.Co-solvents are also added to the pigment flush to provide improvedsolvency or reduce viscosity. Co-solvents may also be added to thefinished ink to adjust viscosity or dissolve additives.

Cyclohexanoic acid diesters, particularly esters of C₂ through C₆alcohols, are useful as co-solvents in printing ink formulations. Thestructure and molecular weight of these diesters provides the necessarysolvency strength and appropriate evaporation profiles to displacecompetitive products like TXIB, etc.

The esters are also useful as LVP fluids are specific Volatile OrganicCompounds (VOC) with Low Vapour Pressure (LVP) that meet the LVP-VOCexemption criteria established in California—s Consumer ProductsRegulation and in the USEPA National Volatile Organic Compound EmissionStandards for Consumer Products.

Cyclohexanoic acid diesters of C₂ through C₆ alcohols meet the vapourpressure criterion specified in both the federal and state consumerproduct regulations. These diesters will be excellent performers inproduct categories where the use of an organic LVP solvent or carrier isneeded to meet performance requirements. Recommended applications forLVP diesters in consumer products include household products, automotivechemicals, insecticides and personal care products. A complete list ofall products (divided into 24 product categories) can be obtained fromCARB and/or the EPA. These diesters can be formulated into all of thelisted products.

An example would be the replacement of d-limonene. D-limonene ispromoted as a ‘natural’ carrier in consumer products. Manufactures ofconsumer products are concerned with d-limonene's supply insecurity,inconsistent quality and high cost. The cyclohexanoic add diestersprovide performance and environmental benefits over products liked-limonene: consistent product quality, higher flash points,non-reportable VOC status, higher level of biodegradability and strongersolvency for better cleaning power.

The diesters can be used neat or in emulsions as desired. The diestersare compatible with typical materials selected for packaging and aerosolvalving systems. They are also compatible with commonly used aerosolpropellants.

The esters of cyclohexanoic carboxylic acid described herein may also beused as coalescers in latex coatings. There are a variety of polymersused in waterborne coatings today. The most common polymers are acrylicpolymers, polyvinyl acetate ethylene, vinyl acetate copolymers andpolymers of and vinyl ester. Most waterborne formulations require smallamounts of organic solvents to aid in the coalescence of the polymerparticles. Cyclohexanoic acid diesters of C₂ thorough C₆ alcohols areuseful as coalescing aids. These diesters possess a number of uniqueproperties which are often difficult to find in a single solvent: (1)limited water miscibility, (2) hydrolytic stability, (3) properevaporation rates and (4) strong solvency to coalescence the polymerparticles.

Glycol ethers are currently used as coalescers (DM, DE, DP, DB, PPHetc). These are entirely or partially soluble in water, which has anegative effect on coalescing power and leads to poor hydrolyticstability. Due to their low water solubilities, the cyclohexane diesterswill partition into the polymer phase, exhibiting excellent coalescingpower. Due to water immiscibility and steric hindrance, the diestersexhibit good hydrolytic stability.

Important in the formulation of a waterborne coating is the evaporationrate of the water/solvent mixture. As the coating dries, it is desirablethat the water and solvent evaporate at rates such that theconcentration of solvent increases over time. Depletion of the solventprior to the water leads to poor coalescence. The evaporation rates ofthe diesters may be controlled by selection of molecular weight toprovide the flexibility to formulate efficiently and balance the impactof varying humidity levels.

The ester structure coupled with the cyclohexanoic ring providescoalescing power, the stability to fuse polymer particulars to form asmooth continuous film at low temperatures. The diesters should showexcellent film forming behaviour across the range of latex polymers.

The odour of the coalescer in an interior coating is important. Thediesters have little odour.

The esters described herein may also be used as plasticisers in masticsand sealants which seal off to provide a flexible joint betweendifferent materials to exclude dust, dirt, moisture or chemicals and toreduce noise, vibration and to insulate or to serve as space fillers. Anincreasing amount of sealant and mastics are produced on the basis ofpolyurethane, acrylics or polysulphides. The majority of these productsare containing plasticiser in the range of 1 to 30%.

In addition to the plasticising effect, the esters of cyclohexanoiccarboxylic acids also serve as a viscosity modifier, a wetting agent forthe filler and any substrate where the mastic and sealant is applied.Another advantage of the cyclohexanoates is the lower viscosity comparedto the currently used phthalates or alkyl sulphonic esters of phenol.This eases the processing of the sealant and mastics.

Examples of the components used in such mastic and sealant compositionsinclude:

Silicones:

(Pre)polymer, crosslinking agent, non-reactive plasticiser, activefillers (carbon black, fumed silica), filler (CaCO₃), pigment, dryingagent, adhesion promoter.

Polyurethanes:

Polymer system (either 2 separate components, to be reacted in-situ or1-C ‘Pre-polymer’), plasticiser, drying agent (molecular sieve, CaO,Portland cement), active filler (fumed silica, carbon black), filler(CaCO₃), miscellaneous (pigments, antioxidants, UV-stabiliser, adhesionpromoters).

Polysulphides:

Polymer system, plasticiser, active filler (carbon black, fumed silica),CaCO₃, miscellaneous (adhesion promoter, pigments), oxidants (for 2-C:PbO₂, MnO₂, for 1-C: CaO, initiated by moisture).

Polyacrylates:

Polymer (reacted), plasticiser, solvent, filler (CaCO₃) miscellaneousadditives.

Butyl/PIB Sealant

Polymer, plasticiser, filler (active and inactive), antioxidants, curingagents, solvents.

It is expected that cyclohexanoates are showing an improved performancein terms of weathering and cold flexibility of the final product versusthe currently used plasticisers in these mastics and sealantapplications.

In a further embodiment the esters of cyclohexanoic acids describedherein are used as polymerisation media particularly for the products ofacrylic coating applications where it is desirable to utilise resinshaving low molecular weight and narrow molecular weight distribution inorder to achieve workable spray viscosities. To reducemolecular/weights, higher polymerisation temperatures are oftenrequired. Since high solids acrylic resin polymerisations are typicallyconducted at the reflux temperature of the polymerisation media, thechoice of the media is based on its boiling point, chain transfercharacteristics and solvency.

Cyclohexanoic di-esters particularly those of C₂ through C₆ alcoholsconsiderably expand the base of materials which can be used aspolymerisation media. These diesters will find application as primarysolvents or cosolvents in acrylic polymerisations. The higher boilingranges will produce lower, unique molecular weights and narrow molecularweight distributions, reducing solution viscosities.

Acrylic polymers made in these di-esters will have the added benefit ofhigh electrical resistance for good electrostatic spray performance.

The diesters of cyclohexanoic acid described herein will have unique,higher chain transfer coefficients when used as polymerisation medium.Chain transfer describes the ability of polymerisation media to limitthe molecular weight of a growing polymer by removing the free-radicalgrowth alia from the molecule and using it to initiate a new chain.

The esters described herein may also be used as plasticisers in waterbased adhesives. They can control application characterises such asviscosity or open time. Additional they modify the physical propertiesof the polymer to yield more flexible adhesives capable of performing atlower temperatures.

An example of a latex adhesive composition is as follows:

Base emulsion Homopolymer, copolymer Plasticiser Solvents Aromatic,Ketones Polyvinylalcohol Partially or fully hydrolysed Wetting AgentsNonionics, anionics Humectants Diethylene glycol, glycerin TackifiersExtenders, rosin ester, phenolics Thickeners Cellulosics, starchesDefoamers Silicones Biocides Sodium benzoate, phenol

The average usage level of plasticisers in homopolymers is around 18%and about 9% in copolymers based on the total solids content of theemulsion.

1. A polyvinyl chloride composition comprising 100 parts of polyvinylchloride and from 20 to 200 parts of total plasticizer comprising aplasticizer other than an ester of a cyclohexane carboxylic acid and 7to 30 wt %, based on the weight of the total plasticizer, of adiisononyl ester of a cyclohexane dicarboxylic acid.
 2. The polyvinylchloride composition of claim 1, wherein said polyvinyl chloride ischaracterized by a K value in the range of 65 to
 70. 3. The polyvinylchloride composition of claim 1, wherein said polyvinyl chloride ischaracterized by a K value above
 70. 4. The polyvinyl chloridecomposition of claim 1, wherein said polyvinyl chloride is characterizedby a K value in the range of 60 to
 67. 5. A finished article made by aprocess including at least one step selected from the group consistingof extruding, moulding, and calendering, of a composition according toclaim
 1. 6. The polyvinyl chloride composition of claim 1, wherein saiddiisononyl ester of a cyclohexane dicarboxylic acid is present in theamount of 10 to 20 wt%, based on the weight of the total plasticizer.